Color-encoding and in-situ interrogation of matrix-coupled chemical compounds

A method of identifying a compound of interest in a library of compounds, each of said compounds being bound to a solid support and being produced by a unique reaction series composed of N reaction steps, wherein N is an integer of at least 2, and wherein each compound is produced from components which are independently the same or different, the method comprising:

• (a) dividing a population of solid support into M batches, wherein M is an integer greater than 1;
• (b) reacting each of the M batches of solid support with a component, so that the component forms a bond with the solid support;
• (c) adding to one or more batches, prior to (b), concurrently with (b), or subsequently to (b), one or more tag(s), each tag able to be attached to the solid support and able to be identified by optical interrogation, wherein said one or more tag(s) constitutes a code, which code is uniquely associated with a compound and a corresponding reaction sequence and is determined by optical interrogation;
• (d) recombining all of said M batches after (b) and (c);
• (e) repeating (a) to (d) for N-1 times, or repeating (a) to (d) for N-2 times followed by repeating (a) to (c) once, to produce a library of compounds;
• (f) performing an assay capable of indicating that any compound in the library has a property of interest;
• and
• (g) decoding the code composed of one or more tag(s) to identify the compound associated with the code, wherein tile decoding step is carried out without isolating the solid support comprising the compound having the property of interest from the other solid supports and without detaching any of the tag(s) from the solid support comprising the compound having the property of interest and wherein said decoding step comprises in-situ optical interrogation of the tag(s).